scholarly journals Multicellular growth and sporulation in filamentous actinobacteria require the conserved cell division protein SepX

2021 ◽  
Author(s):  
Susan Schlimpert ◽  
Matthew James Bush ◽  
Kelley Ann Gallagher ◽  
Govind Chandra ◽  
Kim Findlay
Keyword(s):  
Cell Division ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Important Determinant ◽  
Specific Protein ◽  
Cross Wall ◽  
Specific Cell ◽  
Multicellular Development ◽  
Developmental Life Cycle ◽  
Cell Division Protein

Filamentous actinobacteria like Streptomyces undergo two distinct modes of cell division, leading to the partitioning of growing hyphae into multicellular compartments via cross-walls and to the septation and release of unicellular spores. While some progress has been made towards the regulation of sporulation-specific cell division, specific determinants for cross-wall formation and the importance of hyphal compartmentalization for Streptomyces development have remained unknown. Here we describe SepX, an actinobacterial-specific protein that is crucial for both cell division events in Streptomyces. We show that sepX-deficient mutants grow without cross-walls and that this substantially impairs the fitness of colonies and the coordinated progression through the developmental life cycle. Protein interaction studies and live-cell imaging suggest that SepX functions to spatially stabilize the divisome, a mechanism that also requires the dynamin-like protein DynB. Collectively, this work identifies an important determinant for cell division in filamentous actinobacteria that is required for multicellular development and sporulation.

scholarly journals Hyphal compartmentalization and sporulation in Streptomyces require the conserved cell division protein SepX

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Matthew J. Bush ◽  
Kelley A. Gallagher ◽  
Govind Chandra ◽  
Kim C. Findlay ◽  
Susan Schlimpert
Keyword(s):  
Life Cycle ◽  
Cell Division ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Important Determinant ◽  
Specific Protein ◽  
Cross Wall ◽  
Developmental Life Cycle ◽  
Cell Division Protein ◽  
Cellular Development

AbstractFilamentous actinobacteria such as Streptomyces undergo two distinct modes of cell division, leading to partitioning of growing hyphae into multicellular compartments via cross-walls, and to septation and release of unicellular spores. Specific determinants for cross-wall formation and the importance of hyphal compartmentalization for Streptomyces development are largely unknown. Here we show that SepX, an actinobacterial-specific protein, is crucial for both cell division modes in Streptomyces venezuelae. Importantly, we find that sepX-deficient mutants grow without cross-walls and that this substantially impairs the fitness of colonies and the coordinated progression through the developmental life cycle. Protein interaction studies and live-cell imaging suggest that SepX contributes to the stabilization of the divisome, a mechanism that also requires the dynamin-like protein DynB. Thus, our work identifies an important determinant for cell division in Streptomyces that is required for cellular development and sporulation.

scholarly journals Generation of asymmetry during development. Segregation of type-specific proteins in Caulobacter.

1979 ◽  
Vol 81 (1) ◽  
pp. 123-136 ◽  
Author(s):  
N Agabian ◽  
M Evinger ◽  
G Parker
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Messenger Rna ◽  
Cell Types ◽  
Specific Protein ◽  
Soluble Proteins ◽  
Specific Cell ◽  
Daughter Cells ◽  
Specific Proteins ◽  
Entire Cell

An essential event in developmental processes is the introduction of asymmetry into an otherwise undifferentiated cell population. Cell division in Caulobacter is asymmetric; the progeny cells are structurally different and follow different sequences of development, thus providing a useful model system for the study of differentiation. Because the progeny cells are different from one another, there must be a segregation of morphogenetic and informational components at some time in the cell cycle. We have examined the pattern of specific protein segregation between Caulobacter stalked and swarmer daughter cells, with the rationale that such a progeny analysis would identify both structurally and developmentally important proteins. To complement the study, we have also examined the pattern of protein synthesis during synchronous growth and in various cellular fractions. We show here, for the first time, that the association of proteins with a specific cell type may result not only from their periodicity of synthesis, but also from their pattern of distribution at the time of cell division. Several membrane-associated and soluble proteins are segregated asymmetrically between progeny stalked and swarmer cells. The data further show that a subclass of soluble proteins becomes associated with the membrane of the progeny stalked cells. Therefore, although the principal differentiated cell types possess different synthetic capabilities and characteristic proteins, the asymmetry between progeny stalked and swarmer cells is generated primarily by the preferential association of specific soluble proteins with the membrane of only one daughter cell. The majority of the proteins which exhibit this segregation behavior are synthesized during the entire cell cycle and exhibit relatively long, functional messenger RNA half-lives.

scholarly journals Live cell imaging of the hyperthermophilic archaeon Sulfolobus acidocaldarius identifies complementary roles for two ESCRTIII homologues in ensuring a robust and symmetric cell division

2020 ◽  
Author(s):  
Andre Arashiro Pulschen ◽  
Delyan R. Mutavchiev ◽  
Kim Nadine Sebastian ◽  
Jacques Roubinet ◽  
Marc Roubinet ◽  
...  
Keyword(s):  
Cell Division ◽  
Cell Biology ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Halophilic Archaea ◽  
Live Cell ◽  
Tight Coupling ◽  
Dna Compaction ◽  
Cellular Processes ◽  
Daughter Cells

Live-cell imaging has revolutionized our understanding of dynamic cellular processes in bacteria and eukaryotes. While similar techniques have recently been applied to the study of halophilic archaea, our ability to explore the cell biology of thermophilic archaea is limited, due to the technical challenges of imaging at high temperatures. Here, we report the construction of the Sulfoscope, a heated chamber that enables live-cell imaging on an inverted fluorescent microscope. Using this system combined with thermostable fluorescent probes, we were able to image Sulfolobus cells as they divide, revealing a tight coupling between changes in DNA compaction, segregation and cytokinesis. By imaging deletion mutants, we observe important differences in the function of the two ESCRTIII proteins recently implicated in cytokinesis. The loss of CdvB1 compromises cell division, causing occasional division failures and fusion of the two daughter cells, whereas the deletion of cdvB2 leads to a profound loss of division symmetry, generating daughter cells that vary widely in size and eventually generating ghost cells. These data indicate that DNA separation and cytokinesis are coordinated in Sulfolobus, as is the case in eukaryotes, and that two contractile ESCRTIII polymers perform distinct roles to ensure that Sulfolobus cells undergo a robust and symmetrical division. Taken together, the Sulfoscope has shown to provide a controlled high temperature environment, in which cell biology of Sulfolobus can be studied in unprecedent details.

scholarly journals Microtubule Probe for Correlative Super-Resolution Fluorescence and Electron Microscopy

2018 ◽  
Author(s):  
Xiaohe Tian ◽  
Cesare De Pace ◽  
Lorena Ruiz-Perez ◽  
Bo Chen ◽  
Rina Su ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cell Division ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Super Resolution ◽  
Synchronous Fluorescence ◽  
Live Cell ◽  
Fluorescence And Electron Microscopy ◽  
20 Nm ◽  
In Cells

We report a versatile cyclometalated Iridium (III) complex probe that achieves synchronous fluorescence-electron microscopy correlation to reveal microtubule ultrastructure in cells. The selective insertion of probe between repeated α and β units of microtubule triggers remarkable fluorescent enhancement, and high TEM contrast due to the presence of heavy Ir ions. The highly photostable probe allows live cell imaging of tubulin localization and motion during cell division with an resolution of 20 nm, and under TEM imaging reveals the αβ unit interspace of 45Å of microtubule in cells.

scholarly journals Revealing spatio-temporal dynamics with long-term trypanosomatid live-cell imaging

2021 ◽  
Author(s):  
Richard S Muniz ◽  
Paul C Campbell ◽  
Thomas E Sladewski ◽  
Lars D Renner ◽  
Christopher L de Graffenried
Keyword(s):  
Cell Division ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Temporal Dynamics ◽  
Live Cell ◽  
Three Dimensions ◽  
Imaging Method ◽  
Differential Rate ◽  
Pdms Stamp

Trypanosoma brucei, the causative agent of human African trypanosomiasis, employs a flagellum for dissemination within the parasite's mammalian and insect hosts. T. brucei cells are highly motile in culture and must be able to move in all three dimensions for reliable cell division. These characteristics have made long-term microscopic imaging of live T. brucei cells challenging, which has limited our understanding of a variety of important cell-cycle events. To address this issue, we have devised an imaging approach that confines cells to small volumes that can be imaged continuously for up to 24 h. This system employs cast agarose microwells generated using a PDMS stamp that can be made with different dimensions to maximize cell viability and imaging quality. Using this approach, we have imaged individual T. brucei through multiple rounds of cell division with high spatial and temporal resolution. We have employed this method to study the differential rate of T. brucei daughter cell division and show that the approach is compatible with loss-of-function experiments such as small molecule inhibition and RNAi. We have also developed a strategy that employs in-well "sentinel" cells to monitor potential toxicity due to imaging. This live-cell imaging method will provide a novel avenue for studying a wide variety of cellular events in trypanosomatids that have previously been inaccessible.

Advances in the design of cell-permeable fluorescent probes for applications in live cell imaging

2018 ◽  
Vol 54 (97) ◽  
pp. 13641-13653 ◽  
Author(s):  
Samira Husen Alamudi ◽  
Young-Tae Chang
Keyword(s):  
Fluorescent Probes ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Cell Types ◽  
Design Strategy ◽  
Live Cell ◽  
Specific Cell ◽  
Cellular Environment

Advances in the design strategy of cell-permeable small fluorescent probes are discussed. Their applications in imaging specific cell types and intracellular bioanalytes, as well as the cellular environment in live conditions, are presented.

scholarly journals Cell Type Development in Chlamydia trachomatis Follows a Program Intrinsic to the Reticulate Body

2020 ◽  
Author(s):  
Travis J Chiarelli ◽  
Nicole A Grieshaber ◽  
Anders Omsland ◽  
Christopher H Remien ◽  
Scott S Grieshaber
Keyword(s):  
Cell Division ◽  
Chlamydia Trachomatis ◽  
Mathematical Models ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Developmental Cycle ◽  
Cell Type ◽  
Obligate Intracellular ◽  
Reticulate Body ◽  
A Cell

AbstractThe obligate intracellular bacterial pathogen Chlamydia trachomatis (Ctr) is reliant on an unusual developmental cycle consisting of two cell forms termed the elementary body (EB) and the reticulate body (RB). The EB is infectious and utilizes a type III secretion system and preformed effector proteins during invasion, but does not replicate. The RB replicates in the host cell but is non-infectious. This developmental cycle is central to chlamydial pathogenesis. In this study we developed mathematical models of the chlamydial developmental cycle that account for potential factors influencing the timing of RB to EB cell type switching during infection. Our models predicted that two broad categories of regulatory signals for RB to EB development could be differentiated experimentally; an “intrinsic” cell autonomous program inherent to each RB or an “extrinsic” environmental signal to which RBs respond. To experimentally differentiate between these hypotheses, we tracked the expression of Ctr developmental specific promoters using fluorescent reporters and live cell imaging. These experiments indicated that EB production was not influenced by increased MOI or by superinfection, suggesting the cycle follows an intrinsic program that is not influenced by environmental factors. Additionally, live cell imaging of these promoter constructs revealed that EB development is a multistep process linked to RB growth rate and cell division. The formation of EBs followed a cell type gene expression progression with the promoters for euo and ihtA active in RBs, while the promoter for hctA was active in early EBs/intermediate cells and finally the promoters for the true late genes, hctB, scc2, and tarp active in the maturing EB.ImportanceChlamydia trachomatis is an obligate intracellular bacteria that can cause trachoma, cervicitis, urethritis, salpingitis, and pelvic inflammatory disease. To establish infection in host cells Chlamydia must complete a multi cell type developmental cycle. The developmental cycle consists of two specialized cells; the EB which mediates infection of new cells and the RB which replicates and eventually produces more EB cells to mediate the next round of infection. By developing and testing mathematical models to discriminate between two competing hypotheses for the nature of the signal controlling RB to EB cell type switching. We demonstrate that RB to EB development follows a cell autonomous program that does not respond to environmental cues. Additionally, we show that RB to EB development is a function of cell growth and cell division. This study serves to further our understanding of the chlamydial developmental cycle that is central to the bacterium’s pathogenesis.

scholarly journals CSI1, PATROL1, and exocyst complex cooperate in delivery of cellulose synthase complexes to the plasma membrane

2018 ◽  
Vol 115 (15) ◽  
pp. E3578-E3587 ◽  
Author(s):  
Xiaoyu Zhu ◽  
Shundai Li ◽  
Songqin Pan ◽  
Xiaoran Xin ◽  
Ying Gu
Keyword(s):  
Plasma Membrane ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
De Novo ◽  
Cellulose Synthase ◽  
Specific Protein ◽  
Cellulose Synthesis ◽  
Docking Site ◽  
Multiple Components ◽  
Exocyst Complex

Cellulose synthesis occurs exclusively at the plasma membrane by cellulose synthase complexes (CSCs). Therefore, delivery of CSCs to discrete sites at the plasma membrane is critical for cellulose synthesis. Despite their significance, the delivery of CSCs is poorly understood. Here we used proteomics approaches, functional genetics, and live cell imaging to show that the de novo secretion of CSCs is mediated by cooperation among cellulose synthase interactive 1 (CSI1), the plant-specific protein PATROL1, and exocyst complex in Arabidopsis thaliana. We propose that CSI1 plays a role in marking the docking site, which allows CSCs-containing vesicles access to the plasma membrane through its interaction with microtubules. PATROL1 assists in exocytosis by its interaction with multiple components, including CSI1, CSCs, and exocyst subunits. Both PATROL1 and the exocyst complex determine the rate of delivery of CSCs to the plasma membrane. By monitoring the exocyst complex, PATROL1, CSI1, and CSCs dynamics in real time, we present a timeline of events for exocytosis of CSCs. Our findings provide unique insights into the evolution of exocytosis in eukaryotes.

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